Malicious PDF — malware analysis report

Static analysis result for SHA-256 81fd881157bd205c…

MALICIOUS

PDF

92.9 KB Created: 2021-07-06 14:51:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 16e5b429db064cbd6051e7fc9b835ccc SHA-1: 31cf11535b5aa62567b430cd0cf909759b765848 SHA-256: 81fd881157bd205ccf4895fc881438ab702307b79db65475885b985001fa52f3
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The heuristics reveal it functions as a link farm, with numerous URLs pointing to compromised WordPress sites, suggesting it's used to distribute phishing content or further malware. The presence of external URIs and link farms on potentially compromised hosting services supports this assessment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9820

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://pistant.ru/uplcv?utm_term=day+thoughts+in+english
    • http://adanateknikservis.web.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160a9ef80bee38---17252978177.pdf
    • https://grand-forge.ru/wp-content/plugins/super-forms/uploads/php/files/10c0eff7cd1604f6210bed53b428c616/87448172659.pdf
    • https://rcot.org/userfiles/file/59020666043.pdf
    • http://willtorock.com/wp-content/plugins/formcraft/file-upload/server/content/files/16077f0c52d608---wimawovot.pdf
    • http://recruiters-zone.com/wp-content/plugins/formcraft/file-upload/server/content/files/16094a7f8de4aa---87824057909.pdf
    • https://www.denisonlandscaping.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d1919d48121---modejuzo.pdf
    • https://earthchartercities.org/wp-content/plugins/formcraft/file-upload/server/content/files/160c96604225c8---rokurutirisaviduzu.pdf
    • http://www.oknookna.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160c199cc9f335---85242553420.pdf
    • http://geology.ie/wp-content/plugins/formcraft/file-upload/server/content/files/160970c274308a---57185730579.pdf
    • http://xahscw.com/userfiles/file/80162012211.pdf
    • http://tpdw.pl/userfiles/file/99737431605.pdf
    • http://chiangmaicharmingtravel.com/ckfinder/userfiles/files/fewelaf.pdf
    • https://inclinedigital.com/wp-content/plugins/formcraft/file-upload/server/content/files/160882384ce2ac---faxolepaloputug.pdf
    • https://action-roofing.com/wp-content/plugins/super-forms/uploads/php/files/4f8126aee6f11b6408a06f5fb6777ac5/32687396981.pdf
    • http://opalbiosciences.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a4fab3b1b2e---tobigiponegivopelilumupir.pdf
    • http://desagresbrts.com/clients/34568/File/geparufeladoxabeguzex.pdf
    • https://apoc.com.au/wp-content/plugins/super-forms/uploads/php/files/f95c4b3be6f60f009aabbef4b226f6db/57233813952.pdf
    • http://sashtraayurveda.com/ckfinder/userfiles/files/vatofopiz.pdf
    • https://xn--p3t29jo1ed4o4xw.tw/upload/files/vuvelikopekamajaju.pdf
    • http://chaitraglaze.com/uploads/50964810348.pdf
    • http://smartmedicaleg.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bfcd2067e14---jaburuxegukiwasow.pdf
    • http://capital96.com/userfiles/file/7912377312.pdf
    • http://nc2e.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1607726672e43f---wenalokevu.pdf
    • http://gibisch.org/files/files/17388501287.pdf
    • https://lashmakerpro.it/wp-content/plugins/super-forms/uploads/php/files/klumj3m5agudc60mq3opc09vf6/napasirebosazujedago.pdf
    • http://bjjiffy.com/upload/89617715175.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00010c63.bin
2c391c89aeb82f4fc44480b2b314a892cd26c60f65fc2b6b59e7c0a66d4c7fa4
pdf-font-stream PDF embedded font (sfnt) at offset 0x10C63 10500 bytes
font_01_sfnt_off00012445.bin
bfb2e8777cfe17d4a1f9d2bf772021e530b270edab12227c855946cf71e1bb08
pdf-font-stream PDF embedded font (sfnt) at offset 0x12445 16252 bytes
font_02_sfnt_off00014e2e.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x14E2E 16792 bytes